Power source for control equipment

ABSTRACT

A power source for control equipment which is designed so that even if one or more independent power sources (700) are added to a main power source (600), the power source arrangement, as viewed from the control equipment supplied with power therefrom, can always be regarded as if one power source were connected thereto. The operative state of control circuit power sources (601, 701) provided in the main power source (600) and the additional power source (700) is detected by control circuit power source abnormality detecting circuits (603, 703), and the operative state of driving power sources (602, 702) provided in the main power source (600) and the additional power source (700) is detected by driving power source abnormality detecting circuits (604, 704). All the driving power sources (602, 702) are turned ON substantially concurrently after the outputs from all the control circuit power sources (601, 701) have reached their normal state, and they are turned OFF substantially concurrently when the output from any one of the control circuit power sources (601, 701) has become abnormal. An enable signal (EN), which is sent to the control equipment, is turned ON after all the control circuit power sources (601, 701) and driving power sources (602, 702) have reached their normal operative state, and is turned OFF when an abnormality has occurred in any one of the power sources.

BACKGROUND OF THE INVENTION

The present invention relates to a control equipment power source forsupplying power to control equipment, such as numerical controlequipment.

In general, control equipment, such as numerical control equipment,contains a memory circuit, an I/O interface circuit and so forth inaddition to a control circuit, such as a processor. In the case wherethe control circuit and the I/O interface circuit and so on operate ondifferent drive voltages, a control equipment power source arrangementis required that provides a power source for supplying electric powernecessary for operating the control circuit (which power source willhereinafter be referred to as the control circuit power source) and apower source for supplying electric power necessary for driving thememory circuit for its read/write operations and for driving the I/Ointerface circuit (which power source will hereinafter be referred to asthe driving power source).

Further, in this kind of control equipment,

1. Various check functions for preventing malfunction are includedcorresponding to the controlled systems but, in many cases, these checkfunctions are not assured in the case of an abnormality in the powersource system;

2. It is desired that stored contents of various memory circuits beretained at the time of the power source being ON and OFF; and

3. It is desired that no unnecessary signals be sent from the interfacecircuit to a controlled system, for instance, a machine tool in atransient state at the time of the ON-OFF operation of the power source.

For the abovesaid reasons, the control equipment power sourcearrangement is required to have the following functions:

(1) A function of detecting power source abnormalities and cutting offthe power source for preventing malfunctions resulting therefrom;

(2) maintenance of a power down sequence for preventing malfunctions atthe time of the ON-OFF operation of the power source; and

(3) a function of quickly providing power source OFF information to thecontrol equipment to stop, for example, the read/write operation of thememory circuit.

To achieve such functions as mentioned above, according to the priorart, for example, as shown in FIG. 1, a control equipment power source102 having a control circuit power source 100 and a driving power source101 is provided with a control circuit power source abnormalitydetecting circuit (hereinafter referred to as the EC power sourceabnormality detecting circuit) 103 for detecting abnormalities in thecontrol circuit power source 100 and a driving power source abnormalitydetecting circuit (hereinafter referred to as the ED power sourceabnormality detecting circuit) 104 for detecting abnormalities in thedriving power source 101, and outputs from the both detecting circuitsare processed to perform a power down sequence such, for instance, asshown in FIG. 2, thereby performing the above-mentioned functions (1)and (3).

That is, when a power source switch 105 is turned ON to connect an ACpower source 106 to the control equipment power source 102, an output Ecfrom the control circuit equipment power source 100 is caused to risefirst and then, at the moment when the output Ec reaches its steadystate, an output Ed from the driving power source 101 is caused to rise.At the moment when the outputs Ec and Ed both reach the steady state, anenable signal EN, which informs control equipment 107 of the presence orabsence of a power source abnormality, is turned ON, thereby preventingmalfunction of the control equipment 107 and a controlled system 108.When a power source abnormality is detected by the detecting circuits103 and 104, the enable signal EN is immediately turned OFF and, after apredetermined period of time, the driving power source 101 is forciblyturned OFF and the power source switch 105 is turned OFF by a switchcontrol signal or an alarm signal ALM, by which the driving power sourceoutput Ed is completely turned OFF before the output Ec from the controlcircuit power source 100 becomes unstable as shown in FIG. 2, thuspreventing malfunction. Further, since the enable signal EN is turnedOFF first, the operation of the memory circuit can be stopped quicklywhen the power source is turned OFF.

In such control equipment as mentioned above, it happens that when thecontrol function is extended, for instance, when the number of axes tobe controlled is increased in numerical control equipment, the powersource capacity becomes insufficient only with the control equipmentpower source 102 shown in FIG. 1 and one more power source must beprovided. For example, there are some occasions when the addition of anextension 300 to the control equipment 107 is accompanied by theprovision of a driving power source 301 alone as shown in FIG. 3, acontrol circuit power source 400 alone as shown in FIG. 4 or a controlcircuit power source 500 and a driving power source 501 as shown in FIG.5. In FIGS. 3 to 5, the parts corresponding to those in FIG. 1 areidentified by the same reference numerals, and 302 indicates increasedpower sources.

In such a compound power source in which an additional power source isprovided separately from a main power source, it is necessary that theaforementioned functions be satisfied as a whole. The prior art merelyadopts an arrangement such that only the main power source performs sucha power down sequence as shown in FIG. 2, or the main power source andthe additional power source execute the above-described power downsequence independently of each other. Accordingly, the prior art hasdefects that, for example, even if the additional power source is brokendown, the main power source continues to operate, that the sequenceshown in FIG. 2 is not satisfied between the output Ec₁ from the controlcircuit power source of the main power soruce and the output Ed₂ fromthe driving power source of the additional power source, and that sincethe compound power source, as viewed from the side of the controlequpment, cannot be regarded as one power source connected thereto,processing in the case of a power source abnormality is complex anddifficult on the side of the control equipment.

SUMMARY OF THE INVENTION

The present invention has overcome such defects of the prior art, andhas for an object to provide a power source system by which theaforementioned functions (1) to (3) can be performed in a controlequipment power source arrangement provided with one or more additionalpower sources each having housed therein at least one of a controlcircuit power source and a driving power source, separately from a mainpower source having housed therein a control circuit power source and adriving power source, and by which the power source arrangement, asviewed from the control equipment, can always be regarded as if onepower source were connected thereto regardless of whether the additionalpower source is provided. The invention will hereinafter be described indetail in connection with its embodiment.

According to the present invention, EC power source abnormalitydetecting circuits and ED power source abnormality detecting circuitsare provided in a main power source and an additional power source. Whenit is decided from a signal obtained by ORing the detected outputs fromall the EC power source abnormality detecting circuits that all controlcircuit power sources have reached their normal state, all driving powersources are turned ON substantially simultaneously, and when it isdecided the abnormality has occurred in any one of the control circuitpower sources, all the driving power sources are substantiallyconcurrently turned OFF after a predetermined period of time.Furthermore, when it is decided from a signal obtained by ORing thedetected outputs from both types of circuits that all the controlcircuit power sources and driving power sources have reached theirnormal state, an enable signal is turned ON, and when it is decided thatabnormality has occurred in any one of the power sources, the enablesignal is turned OFF and a power source switch is turned OFF.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the arrangement of a conventional controlequipment power source;

FIG. 2 is a waveform diagram explanatory of its operation;

FIGS. 3 to 5 are block diagrams showing examples of additional powersources;

FIG. 6 is a circuit diagram illustrating the principal part of thearrangement of the device embodying the present invention; and

FIG. 7 is a diagram explanatory of its operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 6 is a circuit diagram illustrating the principal part of thearrangement of an embodiment of the present invention. Reference numeral600 indicates a main power source having housed therein a controlcircuit power source 601 and a driving power source 602, 700 anadditional power source having housed therein a control circuit powersource 701 and a driving power source 702, and 800 a power source switchfor connecting and disconnecting the main power source 600 and theadditional power source 700 from an AC power source 801, which powersource switch can be manually turned ON and OFF by an operator and isforcibly turned OFF by an alarm signal ALM described later.

The main power source 600 is provided with an EC power sourceabnormality detecting circuit 603, and an ED power source abnormalitydetecting circuit 604. As these detecting circuits 603 and 604, use canbe made of detecting circuits, for instance, of the type for comparinginput and output voltages of the power sources 601 and 602 withreference voltages to detect abnormality of the power sources. Detectedoutputs or detection signals Ecal₁ and Edal₁ from the both detectingcircuits 603 and 604 are provided via an OR circuit 605 to the base of atransistor 606 making a combining circuit, and the detected output Ecal₁from the EC power source detecting circuit 603 is also applied to thebase of a transistor 607.

The additional power source 700 is provided with an EC power sourceabnormality detecting circuit 703 for detecting abnormality of thecontrol circuit power source 701 and an ED power source abnormalitydetecting circuit 704 for detecting abnormality of the driving powersource 702. As is the case with the main power source 600, detectedoutputs or detection signals Ecal₂ and Edal₂ from the both detectingcircuits 703 and 704 are ORed by an OR circuit 705 and the ORed outputis provided to the base of a transistor 706 making another combiningcircuit, and the detected output Ecal₂ from the EC power sourceabnormality detecting circuit 703 is also applied to the base of atransistor 707.

The collector of the transistor 606 is connected to one input terminalof each of AND circuits 608 and 609 and to the collector of thetransistor 706 via an additional power source interface line 900.Accordingly, there is provided on the additional power source interfaceline 900 an indication signal or a NOR logical signal of the detectedoutputs from all the EC power source abnormality detecting circuits 603and 703 and all the ED power source abnormality detecting circuits 604and 704. Further, a circuit 610 provided in the main power source 600 isa time constant circuit having a set time delay T₁, which is started atthe time of turning ON the power source switch 800 and, after the timeT₁, continues to apply a logic "1" to the AND circuits 608 and 609. As aresult, when all the control circuit power sources and driving powersources reach their normal state, an enable signal EN is turned ON atthe time T₁ after turning ON the power source switch 800. When anabnormality occurs in any one of the control circuit power sources 603and 703 or the driving power sources 604 and 704 while in operation, theenable signal EN is immediately turned OFF and, at the same time, thealarm signal ALM is applied to the power source switch 800.

The collector of the transistor 607 is connected to an input terminal ofa delay circuit 611 of having a delay time T₂ making a driving powersource control circuit and, further, it is connected via an additionalpower source interface line 901 to the transistor 707 which has itscollector connected to an input terminal of a delay circuit 711similarly having the delay time T₂ and making another power sourcecontrol circuit. Accordingly, there is provided on the additional powersource interface line 901 another indication signal or a NOR logicoutput signal of the detected outputs from all the EC power sourceabnormality detecting circuits 603 and 703.

The delay circuits 611 and 711 are started by the above-described NORlogic signal on the additional power source interface line 901 when allthe control circuit power sources 601 and 701 become normal and, afterthe time T₂, turn ON the driving power sources 602 and 702 substantiallyat the same time by generating a control signal. Further, they arestarted also when any one of the control circuit power sources becomesabnormal and, after the time T₂, they turn OFF the driving power sources602 and 702. In this embodiment the ON-OFF operation of the drivingpower sources is controlled by the delay circuits 611 and 711 having thesame construction, however, delay may also be effected by differentcircuits.

In the above arrangement, the OR circuits 605 and 705, the transistors606 and 706, the additional power source interface line 900, the ANDcircuits 608 and 609 and the time constant circuit 610 make up a controlcircuit which performs the ON-OFF control of the enable signal EN andthe alarm signal ALM, and the transistors 607 and 707, the additionalpower source interface line 901 and the delay circuits 611 and 711 makeup a control circuit which performs the ON-OFF control of the drivingpower souces 602 and 702 in accordance with the aforementioned sequence.

FIG. 7 is a diagram showing variations in the outputs Ec₁ and Ec₂ fromthe control circuit power sources, the outputs Ed₁ and Ed₂ from thedriving power sources and the enable signal EN in the case where thedevice of FIG. 6 is operated. Referring now to FIG. 7, the operation ofthe device of FIG. 6 will be described.

When the power source switch 800 is turned ON by the operator, thecontrol circuit power sources 601 and 701 are started at first and theiroutputs Ec₁ and Ec₂ rise with some dispersion therein or time delay asshown in FIG. 7. When all the control circuit power sources reach theirnormal state, the additional power source interface line 901 becomes ahigh-level to start the delay circuits 611 and 711, by which the drivingpower source outputs Ed₁ and Ed₂ rise as shown in FIG. 7. When all thecontrol circuit power source outputs Ec₁ and Ec₂ and driving powersource outpus Ed₁ and Ed₂ have risen to reach their normal state, theadditional power source interface line 900 becomes the high-level toopen the AND circuit 608 and, after the time T₁, the enable signal EN isturned ON.

Next, when the power source switch 800 is turned OFF by the operator,abnormality of the control circuit power sources 601 and 701 is detectedby the EC power source abnormality detecting circuits 603 and 703. As aconsequence, the additional power source interface line 800 becomes alow-level and the enable signal EN is immediately turned OFF and, afterthe time T₂, all the driving power sources are forcibly turned OFF.Thereafter the control circuit power source outputs Ec₁ and Ec₂gradually fall.

Moreover, in the case of an abnormality occurring in any one of thecontrol circuit power sources or the driving power sources, since theadditonal power source interface line 900 becomes the low-level, theenable signal EN is immediately turned OFF and, at the same time, thepower source switch 800 is turned OFF by the alarm signal ALM and, afterthe driving power sources 602 and 702 are forcibly turned OFF, thecontrol circuit power source outputs Ec₁ and Ec₂ fall. Also in thiscase, the aforementioned power down sequence is satisfied.

As has been described in the foregoing, according to the presentinvention, in a control equipment power source arrangement which has, inaddition to a main power source having a control circuit power sourceand a driving power source, one or more additional power sources eachhaving at least one of the aforementioned control circuit power sourceand the aforementioned driving power source, there are provided in eachof the main power source and the additional power source an EC powersource abnormality detecting circuit and ED power source abnormalitydetecting circuit. When it is decided from a signal obtained by ORingthe detected outputs from all the EC power source abnormality detectingcircuits that all the control circuits have reached their normal state,all the driving power sources are turned ON substantially concurrently;when it is decided that an abnormality has occurred in any one of thecontrol circuit power sources, all the driving power sources are turnedOFF substantially at the same time after a predetermined period of time;when it is decided from a signal obtained by ORing the detected outputsfrom all the EC and EC power source abnormality detecting circuits thatall the control circuit power sources and driving power sources havereached their normal state, an enable signal is turned ON; and when itis decided that an abnormality has occurred in any one of the powersources, the enable signal is turned OFF and, at the same time, a powersource switch is turned OFF. Since the aforementioned functions (1) to(3) are thus performed in the control equipment power source arrangementas a whole, it is possible to prevent, with certainty, malfunction inthe transient state at the time of turning ON and OFF the power sources.In addition, since the power source arrangement, as viewed from thecontrol equipment, can always be regarded as if one power source wereconnected thereto regardless of the presence or absence of theadditional power source, processing in the case of the occurrence of apower source abnormality can be effected with ease.

We claim:
 1. A compound power source for control equipment, comprising:apower source switch; a main power source and at least one additionalpower source, each of said main and additional power sources operativelyconnected to said power source switch and comprising:control circuit anddriving power sources operatively connected to said power source switch;a control circuit power source abnormality detecting circuit,operatively connected to said control circuit power source, fordetecting abnormality of said control circuit power source andgenerating an output; a driving power source abnormality detectingcircuit, operatively connected to said driving power source, fordetecting abnormality of said driving power source and generating anoutput; a control circuit, operatively connected to said driving powersource, said control circuit power source abnormality detecting circuitand said driving power source abnormality detecting circuit, for turningON said driving power source a predetermined period of time after saidcontrol circuit power source abnormality detecting circuit decides thatsaid control circuit power source has become normal, and for turning OFFsaid driving power source a predetermined period of time after saidcontrol circuit power source abnormality detecting circuit decides thatabnormality has occurred in said control circuit power source; and an ORcircuit, operatively connected to said control circuit power sourceabnormality detecting circuit and said driving power source abnormalitydetecting circuit, for ORing the outputs of said control circuit powersource abnormality detecting circuit and said driving power sourceabnormality detecting circuit and generating an output; a firstinterface, operatively connected to all said driving power sources andall said control circuit power source abnormality detecting circuits,for turning ON all said driving power sources substantially concurrentlywhen it is decided from a signal obtained by ORing the outputs from allsaid control circuit power source abnormality detecting circuits thatall said control circuit power sources have reached their normal state,and for turning OFF all said driving power sources substantiallyconcurrently after a predetermined period of time when it is decidedthat abnormality has occurred in any one of said control circuit powersources; and a second interface, operatively connected to all said ORcircuits, said driving power source abnormality detecting circuits, thecontrol equipment and said power source switch, for turning ON an enablesignal to be sent from said main power source to the control equipmentwhen it is decided from the outputs from all said OR circuits that allsaid control circuit power sources and all said driving power sourceshave reached their normal state, and for turning OFF the enable signaland said power source switch, by a signal output only by said main powersource, when it is decided that abnormality has occurred in any one ofsaid control circuit power sources and said driving power sources.
 2. Acompound power source and control system for control equipment,comprising:a power source switch; a first power source operativelyconnected to said power source switch, comprising:a first controlcircuit power source operatively connected to said power source switchand the control equipment; a first driving power source operativelyconnected to said power source switch and the control equipment; andfirst control means, operatively connected to said first control circuitpower source, said first driving power source, said power source switchand the control equipment, for detecting an abnormality in said firstcontrol circuit power source and said first driving source, forgenerating a switch control signal, for generating an enable signal, forgenerating a first driving power source control signal and forgenerating first and second indication signals; and at least one secondpower source operatively connected to said power source switch, saidfirst power source and the control equipment, comprising:a secondcontrol circuit power source operatively connected to said power sourceswitch and the control equipment; a second driving power sourceoperatively connected to said power source switch and the controlequipment; and second control means, operatively connected to saidsecond control circuit power source, said second driving power sourceand said first control means, for detecting abnormality in said secondcontrol circuit and driving power sources, for generating third andfourth indication signals and for generating a second driving powersource control signal, the power switch control signal and enable signalbeing generated in dependence upon the second or fourth indicationsignals, and the first and second driving power source control signalsbeing generated with a first delay after one of said first and seconddriving power source abnormality detecting circuits have detectedabnormality and after both said first and second driving power sourceshave returned to normal following abnormality detected in one of saidfirst and second driving power sources.
 3. A compound power source andcontrol system for control equipment as recited in claim 2, wherein saidfirst control means comprises:a first abnormality detecting circuit,operatively connected to said first control circuit power source, forgenerating a first detection signal; a second abnormality detectingcircuit, operatively connected to said first driving power source, forgenerating a second detection signal; first driving control means,operatively connected to said first abnormality detecting circuit, saidsecond control means and said first driving power source, for generatingthe first indication signal in dependence upon the first detectionsignal and for generating the first driving power source control signalin dependence upon the first detection signal or the third indicationsignal; first combining means, operatively connected to said first andsecond abnormality detecting circuits and said second control means, forgenerating the second indication signal in dependence upon the first orsecond detection signals; and control and signal means, operativelyconnected to said first combining means, said second control means, saidpower source switch and the control equipment, for generating the enablesignal and the switch control signal in dependence upon the second orfourth indication signals after a predetermined second delay.
 4. Acompound power source and control system for control equipment asrecited in claim 3, wherein said second control means comprises:a thirdabnormality detecting circuit, operatively connected to said secondcontrol circuit power source, for generating a third detection signal; afourth abnormality detecting circuit, operatively connected to saidsecond driving power source, for generating a fourth detection signal;second driving control means, operatively connected to said thirdabnormality detecting circuit, said second driving power source and saidfirst driving control means, for generating the third indication signalin dependence upon the third detection signal and for generating thesecond driving power source control signal in dependence upon the thirddetection signal or the first indication signal; and second combiningmeans, operatively connected to said third and fourth abnormalitydetecting circuits and said control and signal means, for generating thefourth indication signal in dependence upon the third or fourthdetection signals.
 5. A compound power source and control system forcontrol equipment as recited in claim 4, wherein said first and seconddriving control means each comprise:a first transistor operativelyconnected to the respective said abnormality detecting circuit and theother of said first and second driving control means; and a delaycircuit, operatively connected to said first transistor, the respectivesaid driving power source and the other of said first and second drivingcontrol means.
 6. A compound power source and control system for controlequipment as recited in claim 5, wherein said first and second combiningmeans each comprise:an OR circuit operatively connected to therespective ones of said first through fourth abnormality detectingcircuits; and a second transistor operatively connected to said ORcircuit and said control and signal means.
 7. A compound power sourceand control system for control equipment as recited in claim 6, whereinsaid control and signal means comprises:a time constant circuitoperatively connected to said power source switch; a first AND gateoperatively connected to said time constant circuit, said secondtransistor of both said first and second combining means and the controlequipment; and a second AND gate operatively connected to said timeconstant circuit, said second transistor of both said first and secondcombining means and said power source switch.